1. Area of the Art
The present invention relates to vehicle safety devices, and more particularly to a device which punctures an inflating air bag in controlled fashion so as to soften the surface of the inflating air bag and prevent injury to the vehicle occupant.
2. Description of the Prior Art
It is known in the art to provide arrangements for venting an inflating air bag to prevent injury to the vehicle occupant. Examples of such include U.S. Pat. No. 5,603,526 of Buchanan in which an air bag cushion has frangible vent coverings and vent openings which permit inflation gas to exit the cushion and provide the proper pressure reduction for preventing injury to the passenger. In U.S. Pat. No. 5,725,244 of Cundill, an air bag has a venting mechanism that allows inflation gas to vent from an inflation chamber through an expandable venting member. When the inflation pressure in the air bag reaches a preselected level, the frangible portion of the retaining member breaks and the venting member is expanded through the broken portion allowing the inflation gas to vent to the atmosphere.
Still other arrangements known in the art combine with a vehicle seat belt system to protect the vehicle occupant from injury. In U.S. Pat. No. 6,273,467 of Berke et al., a surgical shield mounted on the shoulder strap of the seat belt system prevents rubbing of the strip on a sensitive or physically impaired body area such as a heart pacer, chest injuries, or the like. U.S. Pat. No. 6,439,333 of Dömens et al. describes a sensor system for inflating an air bag in a differentiated way. The position of the vehicle occupant is determined by using the seat belt as an active reference position. The distance between the seat belt and known points within the vehicle determines the position of the seat belt and thus the vehicle occupant. U.S. Pat. No. 6,557,895 of Haack et al. describes a protective pad similar to that described in U.S. Pat. No. 6,273,467 of Berke et al. Similarly, U.S. Pat. No. 6,576,808 of Dreyer describes a protective device for a sensitive or vulnerable area of the chest of the seat belt wearer.